1. Field of the Invention
The present invention relates to a recording apparatus for recording onto a recording medium in accordance with input information from an external apparatus such as a host computer or the like.
2. Related Background Art
The recording apparatus such as a printer or the like receives a print code and a control command which are transmitted from the host computer and records onto a recording medium. In a conventional printer, the function is low, the number of control commands is small, and a structure is simple. However, in recent years, a type of printer called a non-impact printer such as a laser beam printer or the like has been developed (U.S. Pat. No. 4,059,833). Such a kind of printer expresses characters or images as a set of dots and has a very high function. With the improvement of the function, the number of control commands to instruct the functions is also increased and the structure of the control command becomes more and more complicated. For example, in the case where a font of a character to be printed is designated and this font is not prepared, there is provided a function such as to select the font of the type which is the nearest to the designated font (U.S. Pat. No. 4,686,525 or to independently make the font character thick in the vertical and lateral directions (U.S. patent application Ser. No. 854,193), or the like. Therefore, the number of errors of the control commands also increases.
However, hitherto, even if an error exists in the control command, the printer merely ignores it and continues the recording without displaying the presence of the error. Therefore, it is impossible to determine whether the result of the recording is correct or not. As a practical example, FIG. 2A shows an example of the print in which when a position moving command exists before "D" is printed at a position indicated at 101 and "D" must be correctly printed at a position indicated at 102, an error is included in the position moving command and "D" is printed at the position 101 because this command has been ignored. However, even if this output result is seen, it is impossible to discriminate the error in the position moving command. In addition, there is a case where an error in one control command exerts an influence on the subsequent control commands. In this case, it is also difficult to find out the cause from the result of the recording. As described above, there is a danger such that even if an error exists in a control command and the erroneous recording was performed, it is difficult to discriminate the presence of the error by merely seeing the result of the recording, so that the recorded paper is erroneously delivered.